The whole concept is a trick right? Nobles and Savages. One tells the truth and the other lies, I find that's all extra info designed to trick us. I don't personally believe any of that info is relevant, the real focus should be on the the "Cannibal" issue.
If there's a tribe of cannibals what do they eat? Humans. Wouldn't a Cannibal be more interested in the other two standing on an island rather then the person floating on a raft? Which means all three are Nobles, or all three are savages. But since the third one called the other two out, I think all three are savages trying to trick you to come on shore
I may be wrong, that's how I see it.